Are there any switches one can get analogue signals from?
MIDI supports both speed and pressure reports from musical keyboards. Without looking, I would guess that they measure speed by timing two or more contact points, and pressure with strain gauges.
If you want position reports, I'd suggest looking for an old industrial keyboard with Hall-effect switches to hack on.
Not sure what I want to do with that information yet but it sounds like fun.
With pressure sensitivity, the keyboard could automatically engage Caps Lock WHEN YOU GET ANGRY.